The invention relates to a disposable lancet combined with a reagent carrying-strip. The lancet has a sharp distal end for piercing the skin of a user, and a reagent carrying strip, which reacts to a blood sample.
The invention furthermore relates to a system for extracting and analysing blood in a body utilizing a disposable lancet in combination with a reagent carrying strip.
Patients with certain illnesses like diabetes must verify several times a day the sugar content of their blood. This is often done by placing a drop of blood on to a reagent carrying strip, which causes the reactive reagent on the strip to react with the blood. Usually the reagent carrying strip carries an enzyme that reacts with the blood component to be measured. The result of the test is read by a blood g lucose meter before or/and after applying blood. Most such blood glucose meters on the market today either read the change of colour due to the chemical reaction, or read the current produced from the chemical reaction between reagent or blood glucose.
The drop of blood is obtained by piercing the tip of a finger or the earlobe using a portable skin pricker e.g. as known from U.S. Pat. No. 4,469,110. Such a skin pricker comprises a disposable lancet, a lancet holder and a body. The holder is, when armed, worked upon by a spring. When firing the skin pricker, the disposable lancet inserted in the holder is shot forward by the spring. By pressing the tip of the finger against the skin pricker the finger is pierced by the sharp end of the lancet. A drop of blood can then be obtained from the punctured finger and placed onto the reagent carrying strip. After use the lancet is disposed of. When the change in the reagent carried on the strip has been measured, the strip is also disposed of.
Next time a blood sample is required, the patient has to place a new lancet in the holder of the skin pricker and get a hold of a new reagent carrying strip. The reagent carrying strips are often carried in a separate container, which is very inconvenient, since such a separate container is often forgotten or mislaid. Some times the container is integrated with the skin pricker, but since the lancet and the reagent carrying strip are two separate pieces, they are often available in an unequal number. The user therefore often runs out of one of the items first. As a result of this the user must always remember to refill the container with the item needed.
In order to avoid these inconveniences the disposable lancets are sometimes combined with the reagent carrying strip. Such blood-sampling units are known from U.S. Pat. No. 5,231,993 and EP A1 164.148. These known units have a lancet, which is sharpened for piercing the tip of a finger and an integrated reagent carrying strip. They are however not designed to be used in a typical skin pricker of the type described above. The force needed to pierce the finger is delivered by the patient, but for many patients it is psychologically difficult to pierce themselves. Such patients prefer to use an ordinary skin pricker with a disposable lancet. The change of the reagent carrying strip in these known blood-sampling units is unreadable by the standard glucose meters on the market, since these are designed to read an inserted rectangular strip.
It is an object of the invention to provide an ordinary disposable lancet for a skin pricker, which lancet is combined with a reagent carrying strip in order to minimise the amount of loose items a diabetes patient has to carry around. It is also an object to provide a disposable lancet combined with a reagent carrying strip, which strip can easily be read in a standard glucose meter.
This is obtained by a disposable lancet combined with a reagent carrying strip comprising a lancet, with a distal end, which is sharpened for piercing the skin of the user, and a reagent carrying strip, which carries a reagent that indicates the concentration of a blood component in a blood sample placed in contact therewith.
The disposable lancet combination is characterized in that the reagent carrying strip is a sheet-like strip having a first side and a second side, which sides are both accessible for the user, and that the lancet is connected to the reagent carrying strip.
The disposable lancet can be inserted in a skin pricker having the attached reagent carrying strip sliding in a groove in the skin pricker, but the reagent carrying strip could also be disengaged from the lancet before inserting the lancet in the skin pricker. In both ways it is assured that the patient always has a reagent carrying strip available when inserting a new lancet in the skin pricker. After the blood sample has been placed on to the reagent carrying strip, the strip is easily inserted in a standard blood glucose meter.
In one embodiment of the disposable lancet according to the invention the lancet is made from a moldable polymeric material, and the reagent carrying strip is attached to the lancet. Attaching the reagent carrying strip to the lancet can be done by gluing the reagent carrying strip to the lancet. If the reagent carrying strip is made from paper or another fibrous material the strip can be fastened to the disposable lancet without the use of glue simply by folding the strip around the lancet and applying heat and pressure. The surface of the lancet will then start to melt, and connect to the reagent carrying strip.
In another embodiment of the disposable lancet combined with a reagent carrying strip according to the invention the reagent carrying strip is made from a moldable polymeric material, which is moulded around the lancet. Instead of making the strip from a fibrous material as paper, the strip can be made by moulding a moldable polymeric material to a very thin sheet-like strip of film, on to which the reagent material is placed. The lancet can be made by another material, and the reagent carrying strip can be attached to the lancet by moulding it around the lancet.
In another embodiment of the disposable lancet combination according to the invention the reagent carrying strip has a number of edges between the first and the second side, and the lancet is attached to the reagent carrying strip at one of these edges. By applying the disposable lancet onto the reagent carrying strip at one of the edges, disconnecting the two items is made very easy.
In an appropriate embodiment of the disposable lancet according to the invention the lancet is connected to a frame, which frame is attached to the edges of the reagent carrying strip. By framing the reagent carrying strip a stiff construction is possible, which accommodates an easy insertion into the glucose meter.
In yet another embodiment of the disposable lancet combined with a reagent carrying strip according to the invention an arm is connecting the lancet to the reagent carrying strip or to the frame framing the reagent carrying strip. The reagent carrying strip can then be situated a distance from the disposable lancet, but still in connection therewith, forming a combined unit.
In an embodiment of the disposable lancet combined with a reagent carrying strip according to the invention the connecting point between the reagent carrying strip or the frame and the disposable lancet or the arm has a weakened tear line. By this the attached reagent carrying strip can easily be separated from the lancet.
In an embodiment of the disposable lancet combined with a reagent carrying strip according to the invention the reagent carrying strip is rectangular. Most glucose meters present on the market accommodate rectangular reagent carrying strips.
It is also an object of the invention to provide a system for extracting and analysing blood in a body utilizing a disposable lancet combined with a reagent carrying strip, where the disposable lancet is kept in the same position both when obtaining the blood sample and when analysing the blood sample. In the known systems of this kind e.g. as known from WO A 95/24233, especially FIG. 25, the blood-coated strip has to be manually moved from the position where it is coated with blood and to the position where the change in the reagent is being measured. This is very inconvenient for the user.
This is obtained by a system for extracting and analyzing blood in a body utilizing a disposable lancet combined with a reagent carrying strip according to any of the preceding embodiments, which system comprises:
a housing including a spring actuated hammer, into which housing the disposable lancet combined with a reagent carrying strip is placed in a guided position,
a button which releases the spring actuated hammer, which then pushes forward the disposable lancet combined with a reagent carrying strip,
means for guiding the disposable lancet combination from a retracted position to a deployed position where the tip of the disposable lancet with reagent carrying strip penetrates the skin of the user,
a sensor which senses the changes in the reagent placed on said reagent carrying strip,
a display for showing a visual readout representing the changes in the reagent which system is characterized in that said sensor is situated in a position in the housing where it can sense the changes in the reagent without manually moving the disposable lancet combined with a reagent carrying strip.
In such a system the disposable lancet combined with a reagent carrying strip just need to be placed in the guided position and fired. There after the user merely has to place a drop of blood onto the reagent carrying strip and to actuate the device, then the change in the reagent is read without removing the disposable lancet combination from the guided position.